Coils, why?
 

Cecil Moore wrote:
John Smith wrote:
A "flattened" coil, first time I see one used is Vincents' DLM, anyone?

Looks like linear loading to me.

All joking aside, the point is, a helical/circular coil is not a magical
arrangement ... but then, you already knew that.

I have constructed shortened antennas using pvc pipe with sets of
parallel holes drilled on each side and the conductor "laced" through
the pipe and forming "loops" on each side of the antenna--if nothing
else, the visual of them provoked responses ... I now use such an
arrangement on the bottom helical of my Vincent 20m (modified gamma.)

Regards,
JS

Coils, why?
 

Owen wrote:
"Not to imply that Efficiency = Q."

It does.

Q = energy stored per cycle / energy lost per cycle. Q = XsubL / R

Efficiency = output / input.

Output is the energy given back by the coil when its field collapses.

Input is the energy required to charge the inductor`s field plus the
energy required to supply the losses.

Net output is equivalent to coil reactance and net input is equivalent
to the effective series resistance loss. Therefo Q = Efficiency.

Best regards, Richard Harrison, KB5WZI

Coils, why?
 

Coils, why?
 

"John Smith" wrote in message
...
John Smith wrote:

Poor old W8JI has taken quite a beating, it is best to realize if mistakes
are made, so should it be, we are only human.


He is not poor and not that old. He does not take the "beating" for no
reason, but in response to some of his extreme statements or fallacies that
he proclaims as a gospel on his web site and on the reflectors. If he was
more human, he would realize some of the mistakes in his
thinking/knowledge/proselytizing, correct them and GIVE a credit where it's
due.

However, this individual has prepared some nice pages, he has a nice way
of writing which are easy to logically follow. Newbies, if they stumble
upon his pages, must surely benefit tremendously.


That is nice and to many useful (better source is ARRL Handbook), but
included in that are some errors and misinformation trumpeted as a gospel
according to W8JI which does not serve the ham community well. He is doing
his web "service" not from purely ham philanthropic reasons, but making
business and monetary gains via "W8JI Engineering" and lately "DX
Engineering" products and promotion. (Using "Engineering" label without
having engineering degree, college degree or being member for engineers
association, required by most states.)


Now, as I have stated, I have no real horse in the particular argument
which dominates this group--I simply wish to recognize his good work and
give him proper credit. If unknowingly slight men of good intentions we
may lose them--NOT a good thing ...

I have a horse in some of the arguments, because when I saw some fallacies
being propagated or when I was attacked by him for some of my statements
about my findings and him trying to play in public forum as "all-knowing
guru" to this "know-nothing" real engineer (with some awarded design
experience and bunch of world records), I simply don't take the crap and
react.
Just a brief unpsychological profile of W8JI: he never admits to be wrong,
he jumps on "dummies" from his high horse, if he finds he might have been
wrong, he will never admit it, but obfuscates the issue, fogs it with smoke
and mirrors, goes quiet for a while and later emerges as a guru
appropriating the critic's idea and proclaiming it as new gospel on his
pages. He likes to criticize the other sources as misleading, while himself
has a plenty of it on his pages. Been there about 5 times and I would be
critical about his "gospel". (And you don't not know about some of the
stuff and backstabbing that goes on off the web pages.)


http://www.w8ji.com/loading_inductors.htm


Prime example of another "wrongo".
The main problem with loading stubs in antenna situations is that they have
RF current flowing on the loading wires, which interact (cancellation) with
the element they are "serving" especially when folded back or forward on the
element (3 wires interacting). The best way, if must to use loading stubs,
is to have them to go 90 degrees off the element. The coil does not have
that effect, there is just drop of current across the coil, while rest of
the current along the element is not disturbed.
This effect is magnified when using in arrays, which was verified in real
life by W6?? when they replaced loading stubs with coils and saw dramatic
improvement in the 3 el. KLM 80 m beam - better gain and remarkable
improvement in the pattern, F/B.


Warm regards to all,

That too, from snowy NE!

JS

73 Yuri, K3BU.us

Coils, why?
 

Hal Rosser wrote:
I tried Linear Loading with a 10-meter Mobile antenna - just to try it out.
If I recall, the performance was about the same as a coil-loaded antenna.
The reason I like coils is that they fit nicely inside (or outside) a piece
of PVC pipe, and makes antenna-making easier.

3D coils are superior to 2D linear loading schemes. So far,
no linear loading scheme can equal the performance of a
high-Q coil with its extra dimensional advantage.
--
73, Cecil http://www.w5dxp.com

Coils, why?
 

Richard Harrison wrote:

...
Best regards, Richard Harrison, KB5WZI


Richard:

I'll break down and be honest, I cannot "dust you off."

However, how much "Q" is there in a straight wire radiator?

And, in "linear loading" that much of an "hinderence?"

You know, I have no horse here either--come to think of it!

Warm regards,
JS

Coils, why?
 

Owen wrote:
"So, you are saying that if a coil has a Q of 500, its efficiency is
500, and that there is more output (power) than input (power)?"

Don`t I wish! Our energy problems would be solved. Owen caught me not
thinking everything through and making a bone-headed mistake. I`ll take
some time to rethink the relation between Q and efficiency.

Best regards, Richard Harrison, KB5WZI

Coils, why?
 

Yuri Blanarovich wrote:
...
73 Yuri, K3BU.us

Yuri, I don't know if we are dealing with cultural differences or not,
but damn dude, you are TOO BIG OF A WASTE OF MY TIME ...

PLONK BIG TIME!

Now ....

Warm regards,
JS

P.S. But still, plonk!

Coils, why?
 

John Smith wrote:
Why not:

___ ___
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
___| |___|


etc.

A "flattened" coil, first time I see one used is Vincents' DLM, anyone?

Regards,
JS

P.S. Excuse the bad ascii graphics ...

Hmm...

Obviously, I have missed something in my "education."

In a front end tuner, sometimes, hi-Q is MOST desirable ...

In my antennas, a Q of 20 to 50 is ok, heck 100 is ok ... I don't see
the point above that ...

Regards,
JS

Coils, why?
 

John Smith wrote:

...
Hmm...

Obviously, I have missed something in my "education."

In a front end tuner, sometimes, hi-Q is MOST desirable ...

In my antennas, a Q of 20 to 50 is ok, heck 100 is ok ... I don't see
the point above that ...

Regards,
JS

Well, too fast there, in traps, a hi-Q is desired by me, but heck, 200
is OK!

JS